package chapter2;

import chapter1.InstallBouncyCastle;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;


/**
 * Basic symmetric encryption example
 */
public class SimpleSymmetricExample extends InstallBouncyCastle {
    public static void main(String[] args) throws Exception {

        byte[] input = new byte[]{
                0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
                (byte) 0x88, (byte) 0x99, (byte) 0xaa, (byte) 0xbb,
                (byte) 0xcc, (byte) 0xdd, (byte) 0xee, (byte) 0xff};
        byte[] keyBytes = new byte[]{
                0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
                0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
                0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17};

        SecretKeySpec key = new SecretKeySpec(keyBytes, "AES");

        Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding", "BC");


        System.out.println("input text : " + Utils.toHex(input));

        // encryption pass

        byte[] cipherText = new byte[input.length];

        cipher.init(Cipher.ENCRYPT_MODE, key);

        int ctLength = cipher.update(input, 0, input.length, cipherText, 0);

        ctLength += cipher.doFinal(cipherText, ctLength);

        System.out.println("cipher text: " + Utils.toHex(cipherText) + " bytes: " + ctLength);

        // decryption pass

        byte[] plainText = new byte[ctLength];

        cipher.init(Cipher.DECRYPT_MODE, key);

        int ptLength = cipher.update(cipherText, 0, ctLength, plainText, 0);

        ptLength += cipher.doFinal(plainText, ptLength);

        System.out.println("plain text : " + Utils.toHex(plainText) + " bytes: " + ptLength);
    }
}
